Device and method for performing a diagnostic test

ABSTRACT

A device and method for performing a point of care diagnostic test for detecting and quantifying at least one analyte in a biological sample (e.g., a body fluid). A device may include an immunoassay apparatus and a holder with an adjustable variable angle stage for positioning the immunoassay apparatus relative to a light source and a detector device so as to optimize the angle of incidence and angle of radiation to optimize an elastic light scattering signal from the immunoassay apparatus. The elastic light scattering signal may be used to quantify the amount of the analyte(s) of interest present in the sample. The device is based upon elastic light scattering, so the variation in the angle of incidence and angle of reflection are optimized to maximize signal generation due to elastic light scattering.

CROSS-REFERENCE TO RELATED APPLICATIONS

The application claims the benefit of and priority to U.S. Prov. Pat.App. Ser. No. 61/533,959 filed 13 Sep. 2011 and entitled “DEVICE ANDMETHOD FOR PERFORMING A DIAGNOSTIC TEST,” the entirety of which isincorporated by reference.

BACKGROUND

Sampling and testing of biological samples and body fluids (e.g.,saliva, blood, urine, fecal matter, foods, plants, fish, minerals,animals, etc) is common for both testing and monitoring humans, fish,animals, and plants for any number of biochemical or physiologicalconditions and, of course, for determining the general state of healthof an organism. For example, sampling and testing of human body fluidsis often performed for point-of-care testing (“POCT”). POCT is definedas medical testing at or near the site of patient care. The drivingnotion behind POCT is to bring the test conveniently and immediately tothe patient. This increases the likelihood that the patient, physician,and care team will receive the results more quickly, which allows forimmediate clinical management decisions to be made. POCT examplesinclude, but are not limited to, blood glucose testing, hormone testing,cardiac pulmonary, gastroenterology, urology, dermatology, neurology,pediatrics, surgical, public health, bioterrorism, food safety, andveterinary and plant pathology testing, metabolic testing (e.g., thyroidstimulating hormone), blood gas and electrolytes analysis, rapidcoagulation testing, rapid cardiac markers diagnostics, drugs of abusescreening, urine testing, pregnancy testing, fecal occult bloodanalysis, food pathogen screening, complete blood count (“CBC”),hemoglobin diagnostics, infectious disease testing, cholesterolscreening cancer testing (e.g. PSA), hormone testing (hCG, LH, FSH),cardiac (troponin), pulmonary, gastroenterology (e.g., H. pyloriantibodies), urology, dermatology, neurology, pediatrics, surgical, andpublic health (Ebola, cholera, HIV), and combinations thereof.

One testing method that is often employed for POCT and more conventionaltesting involves the use of lateral-flow chromatographic immunoassaycassettes. Lateral-flow chromatographic immunoassay cassettes can beused to easily and quickly obtain a variety of qualitative resultsrelating to a number of biochemical and physiological conditions anddisease states of an individual. These kinds of tests require the enduser to simply add a sample to the cassette and then observe the resulta few minutes later. Since such rapid and easy-to-use tests are userfriendly, they are very popular in both the professional and consumermarkets nowadays. Such tests are also very popular in areas where accessto trained health care professionals is limited or where access toproper medical facilities is limited (e.g., poor areas, developingcountries, war zones, etc).

Lateral flow chromatographic immunoassay methods and devices have beendescribed extensively. See, e.g., Gordon and Pugh, U.S. Pat. No.4,956,302; H. Buck, et al., WO 90/06511; T. Wang, U.S. Pat. No.6,764,825; W. Brown, et al., U.S. Pat. No. 5,008,080; Kuo and Meritt,U.S. Pat. No. 6,183,972, EP 00987551A3. Such assays involve thedetection and determination of an analyte substance that is a member ofa specific binding pair consisting of a ligand and a receptor. Theligand and the receptor are related in that the receptor specificallybinds to the ligand, being capable of distinguishing a specific ligandor ligands from other sample constituents having similarcharacteristics. Immunological assays involving reactions betweenantibodies and antigens are one such example of a specific bindingassay. Other examples include DNA and RNA hybridization reactions andbinding reactions involving hormones and other biological receptors. Onewell-known commercial embodiment of this technique is the ClearblueOne-Step Pregnancy Test.

Lateral flow chromatographic immunoassay test cassettes have a number ofdesirable characteristics including their ease of use and broadapplicability to a variety of analytes. Likewise, immunoassay procedurescapable of being carried out on a test strip and which can beadministered in the field or other locations where medical testinglaboratories are not readily available have provided a great benefit tothe diagnosis and control of disease. Currently, however, such lateralflow chromatographic immunoassay tests are generally only capable ofproviding qualitative results. That is, while currently availablelateral flow chromatographic immunoassay test cassettes and cassettereader apparatuses are particularly well-suited for telling apractitioner whether or not one or more test substances are present in asample above a given detection limit, they are poorly suited forproviding quantitative results. There is an ongoing need in the art fordevices and methods that combine the ease of use characteristics oflateral flow chromatographic immunoassay tests with systems that aredesigned to provide quantitative results. Such devices and methods may,for example, allow medical practitioners to diagnose a variety ofconditions at the point of care (e.g., chair-side or essentiallyanywhere in the world) without being tied to a medical facility or atesting laboratory.

BRIEF SUMMARY

A device and method for performing a point of care diagnostic test fordetecting and quantifying at least one analyte in a biological sample(e.g., a body fluid). In one embodiment, the device disclosed herein mayinclude an immunoassay apparatus (i.e., a lateral flowimmunochromatographic assay cassette) and a sample holder with anadjustable variable angle stage for positioning the immunoassayapparatus relative to a light source and a detector device to optimizeelastic light scattering. In another embodiment, the device includes aninterface for a light source (e.g., an optical fiber or light pipe), aninterface (e.g., a collimating lens) for a external digital imager (e.gCCD or CMOS chip), and an adjustable variable angle stage that positionsa lateral flow immunochromatographic assay cassette so as to optimizethe angle of incidence and angle of radiation to optimize an elasticlight scattering signal from the a lateral flow immunochromatographicassay cassette. The device is based upon elastic light scattering, sothe variation in the angle of incidence and angle of reflection areoptimized to maximize signal generation due to elastic light scattering.In one embodiment, the device disclosed herein may include animmunoassay apparatus, a detector device (e.g., a digital camera)positioned to capture at least one image of a visual signal output ofthe immunoassay apparatus, a light source positioned to illuminate theimmunoassay apparatus with at least one wavelength of light selected tointeract with the visual signal output produced by the immunoassayapparatus, and a holder configured to couple the immunoassay apparatusto the detector device in proximity to the light source.

In one embodiment, the first angle between the light source (i.e.,incident light) and the immunoassay apparatus, and the second anglebetween the detector device and the immunoassay apparatus (i.e.,elastically scattered light) is adjustable to improve at least one of asignal-to-noise ratio or a detection limit for the at least one analyte.Optimizing these two angles enables the user to maximize the elasticlight scattering signal from the immunoassay apparatus while minimizingthe non-specific light from the apparatus. In one embodiment, the firstangle between the light source (i.e., incident light) and theimmunoassay apparatus, and the second angle between the detector device(e.g., scattered, emitted, or reflected light) and the immunoassayapparatus is adjustable to improve at least one of a signal-to-noiseratio or a detection limit for the at least one analyte. Optimizingthese two angles enables the user to maximize the scattered, emitted, orreflected (i.e., specific) light from the immunoassay apparatus whileminimizing the non-specific light from the apparatus.

In one embodiment, a single immunoassay device may contain multipletypes of different antibodies each conjugated with different dyes (e.g.,quantum dots) and multiple capture bands each immobilized with differentantibodies. A single light source (e.g., ultraviolet light) illuminatesall dyes (e.g., quantum dots) simultaneously, and the detector device(e.g., a miniature spectrophotometer or a digital camera) captures theemitted signals from multiple bands simultaneously.

In one embodiment, the detector device further includes or can remotelyaccess an interpretive algorithm that is adapted for interpreting and/oraiding interpretation of the results of the immunoassay. Theinterpretive algorithm may include one or more computer storage mediahaving stored thereon computer executable instructions that, whenexecuted by one or more processors (of the detector device), implement amethod for interpreting a numerical value related to the visual signaloutput produced by the immunoassay apparatus in response to the presenceor amount of the at least one analyte present in the sample. In oneembodiment, the computer implemented method includes (1) receiving auser initiated request to convert the visual signal readout of theimmunoassay apparatus to a numerical value, (2) in response to therequest, an act of identifying at least one elastic light scatteringsignal of the immunoassay apparatus, (3) capturing at least one elasticlight scattering signal from the immunoassay apparatus, (4) convertingthe one elastic light scattering signal to at least one numerical valueproportional at least one of an intensity or density of the elasticlight scattering signal, and (5) using the at least one numerical valueto determine an amount or concentration of at least one analyte presentin the sample. This numerical value can then be displayed on a screenlocated on the detector device and/or stored, interpreted, or sent to adatabase. In one embodiment, the computer implemented method includes(1) receiving a user initiated request to convert the visual signalreadout of the immunoassay apparatus to a numerical value, (2) inresponse to the request, an act of identifying at least one visualsignal readout of the immunoassay apparatus, (3) capturing at least onedigital photographic image of the at least one visual signal readout ofthe immunoassay apparatus, (4) converting the at least digitalphotographic image to at least one numerical value proportional to atleast one of an intensity, a density, or a number of pixels in the atleast one digital photographic image of the at least one visual signalreadout of the immunoassay apparatus, and (5) using the at least onenumerical value to determine an amount or concentration of at least oneanalyte present in the sample. This numerical value can then bedisplayed on a screen located on the detector device and/or stored,interpreted, or sent to a database.

In another embodiment, a method for detecting at least one analyte ofinterest in a sample is disclosed. The method includes (1) providing alateral-flow chromatographic immunoassay cassette that includes at leastone ligand immobilized thereon, wherein the at least one ligand iscapable of capturing an analyte of interest on the lateral-flowchromatographic immunoassay cassette (2) applying a liquid sample to thelateral-flow chromatographic immunoassay cassette, wherein the sampleincludes at least one analyte of interest, (3) coupling the lateral-flowchromatographic assay cassette to a sample holder configured to anglethe lateral-flow chromatographic assay cassette in relation to adetector device, and (4) observing the presence of the at least oneanalyte of interest by elastic light scattering. In one embodiment, thedevice includes an illumination source, a miniature spectrophotometer,at least one optical fiber capable of transmitting an illuminating lightfrom the illumination source to the lateral-flow chromatographic assaycassette, a collimating lens capable of transmitting a signal from thelateral-flow chromatographic assay cassette to the miniaturespectrophotometer, and an adjustable variable angle stage configured forholding the lateral-flow chromatographic assay cassette at an anglegreater than or less than zero degrees in relation to the illuminatinglight and the miniature spectrophotometer, wherein the illuminatinglight and the and the miniature spectrophotometer are positioned toilluminate at least a portion of the lateral-flow chromatographic assaycassette and optimize an elastic light scattering signal from thelateral-flow chromatographic assay cassette. In another embodiment, amethod for detecting at least one analyte of interest in a sample isdisclosed. The method includes (1) providing a lateral-flowchromatographic immunoassay cassette that includes at least one ligandimmobilized thereon, (2) applying a liquid sample to the lateral-flowchromatographic immunoassay cassette, wherein the sample includes atleast one analyte of interest, (3) observing an interaction of the atleast one analyte of interest with the at least one ligand immobilizedon the lateral-flow chromatographic immunoassay cassette with a devicethat includes a digital camera device, a light source, and a holderconfigured to couple the lateral-flow chromatographic immunoassaycassette to the digital camera device in proximity to the light source.The holder is adjustable to adjust the angle of the immunoassayapparatus relative to the light source and the digital camera device toimprove at least one of a signal-to-noise ratio or a detection limit forthe at least one analyte of interest. The method further includes (4)querying an interpretive algorithm stored in a computer readable formatin the digital camera device to convert the observed interaction of theat least one analyte of interest with the at least one ligand visualreadout to a numerical value related to the presence or amount of the atleast one analyte of interest present in the sample.

In another embodiment, the present invention provides

1. A system, comprising: an assay apparatus configured for providing asignal in response to at least one analyte of interest in a sample; adetector device; a light source configured to transmit at least onewavelength of light capable of interacting with the signal of the assayapparatus; and a holder configured to couple the assay apparatus to thedetector device in proximity to the light source, wherein the lightsource is positioned to illuminate at least a portion of the assayapparatus and the detector is positioned to capture at least one imageof the illuminated signal.2. The system of claim 1, further comprising an interpretive algorithmstored in a computer readable format and electronically coupled to thedetector device, wherein the interpretive algorithm is configured toconvert the at least one image of the illuminated signal to a numericalvalue related to the presence or amount of the at least one analytepresent in a sample.3. The diagnostic testing system of claim 1, wherein the assay apparatusis a lateral-flow chromatographic assay cassette having at least oneligand immobilized thereon configured for capturing an analyte ofinterest.4. The system of claim 4, wherein the holder includes an electricalconnector configured to draw power from the detector device to power thelight source.5. The system of claim 1, wherein the detector device is a digitalcamera device.6. The system of claim 3, wherein the digital camera device is one of acamera phone or a compact digital camera.7. The system of claim 3, wherein the light source is one of a flash orautofocus illuminator included on the digital camera device.8. The system of claim 1, wherein at least one wavelength filter isinterposed between the light source and the assay apparatus.9. The system of claim 1, wherein the light source includes at least oneof a camera flash, an autofocus illuminator, ambient light, sunlight, anLED light, an incandescent lamp, or a gas-discharge lamp.10. The method of claim 1, wherein the light source is configured toyield at least one wavelength of light selected to convert the signal ofthe assay apparatus to a fluorescent emission signal.11. The system of claim 1, wherein the light source includes at leastone focusing apparatus for focusing the light source on the assayapparatus.12. The system of claim 1, wherein the assay apparatus includes alateral-flow chromatographic assay cassette.13. The system of claim 10, wherein the a lateral-flow chromatographicassay cassette comprises: a base; a strip positioned above the baseincluding a wicking material, wherein the strip includes a distal endand a proximal end; and a sample application zone positioned between thedistal end and the proximal end, wherein a liquid sample applied to thesample application zone diffuses through the absorbent strip from thedistal end to the proximal end, and wherein an analyte of interest, ifpresent in the sample, interacts with at least a first antibodyimmobilized in the absorbent strip to yield a signal that can bedetected by the detector device.14. The system of claim 1, wherein the holder is configured to adjustthe angle of the assay apparatus relative to the light source and thedetector device.15. The system of claim 1, wherein the holder is configured to adjustthe angle of the assay apparatus relative to the light source and thedetector device to improve at least one of a signal-to-noise ratio or adetection limit.16. The system of claim 1, wherein the holder includes a device forautomatically sampling a number of angles of the assay apparatusrelative to the light source and the detector device to improve at leastone of a signal-to-noise ratio or a detection limit.17. A diagnostic testing system, comprising: a lateral-flowchromatographic assay cassette that includes at least one ligandimmobilized thereon configured to interact with at least one analytepresent in a sample to provide a visual readout related to the presenceor amount of the at least one analyte present in the sample; a digitalcamera device; a light source capable of producing light having at leastone wavelength or a range of wavelengths selected to illuminate thevisual readout of the lateral-flow chromatographic assay cassette; aholder configured to couple the lateral-flow chromatographic assaycassette to the digital camera device in proximity to the light source,wherein the holder is adjustable to position the light source toilluminate at least a portion of the lateral-flow chromatographic assaycassette and the camera is positioned to capture at least one image ofthe visual readout; and an interpretive algorithm stored in a computerreadable format in the digital camera device, wherein the interpretivealgorithm is configured to convert the visual readout to a numericalvalue related to the presence or amount of the at least one analytepresent in a sample.18. The diagnostic testing system of claim 17, wherein the digitalcamera device is one of a camera phone or a compact digital camera.19. The diagnostic testing system of claim 17, wherein the sample isselected from the group consisting of a saliva sample, a blood sample, ablood extract, a urine sample, a fecal matter sample, a pathologysample, a plant material, a food sample, and combinations thereof.20. The diagnostic testing system of claim 17, wherein the sampleincludes at least one control substance and at least one test substance.21. The diagnostic testing system of claim 20, wherein the positivecontrol substance is detectable at least one of a different time thanthe at least one test substance or at a wavelength different than thewavelength used to detect the at least one test substance.22. The diagnostic testing system of claim 20, wherein the positivecontrol substance migrates through the lateral-flow chromatographicassay cassette at different rate than the at least one test substance.23. The diagnostic testing system of claim 20, wherein the at least onetest substance includes blood glucose, thyroid stimulating hormone,blood gas and electrolytes analysis, cardiac markers, drugs of abuse, aurine component, a pregnancy hormone marker, fecal occult blood, a foodpathogen, complete blood count (“CBC”), cholesterol, a cancer marker, ahormone, an antibody associated with a pathogen, a pathogen, andcombinations thereof.24. The diagnostic testing system of claim 20, wherein a limit ofdetection for the at least one test substance is within a clinicallyaccepted range.25. The diagnostic testing system of claim 24, wherein the limit ofdetection is a function of at least one of an angle between the digitalcamera device and the light source, an angle between the lateral-flowchromatographic assay cassette and the light source, or an angle betweenthe digital camera device and the lateral-flow chromatographic assaycassette.26. The diagnostic testing system of claim 17, wherein the interpretivealgorithm includes one or more computer storage media having storedthereon computer executable instructions that, when executed by one ormore processors of the digital camera device, implement a method forinterpreting the numerical value related to the presence or amount ofthe at least one analyte present in the sample, the method comprising:receiving a user initiated request to the visual readout of thelateral-flow chromatographic assay cassette to a numerical value; inresponse to the request, an act of identifying at least one visualreadout of the lateral-flow chromatographic assay cassette; capturing atleast one digital photographic image of the at least one visual readoutof the lateral-flow chromatographic assay cassette; converting the atleast digital photographic image to at least one numerical valueproportional to at least one of an intensity, a density, or a number ofpixels in the at least one digital photographic image of the at leastone visual readout of the lateral-flow chromatographic assay cassette;and using the at least one numerical value to determine an amount orconcentration of at least one analyte present in the sample.27. The diagnostic testing system of claim 26, the computer implementedmethod further including at least one of: communicating with anelectronic medical records system via a wireless communication channel;uploading the amount or concentration of the at least one analytepresent in the sample to the electronic medical records system; queryinga decision support algorithm, wherein the decision support algorithmuses the at least one numerical value to support a diagnosis of at leastone condition in a subject and to suggest a course of treatment.28. A method for detecting at least one analyte of interest in a sample,the method comprising: providing a lateral-flow chromatographic assaycassette that includes at least one ligand immobilized thereon; applyinga liquid sample to the lateral-flow chromatographic assay cassette,wherein the sample includes at least one analyte of interest; observingan interaction of the at least one analyte of interest with the at leastone ligand immobilized on the lateral-flow chromatographic assaycassette with a device that includes a digital camera device, a lightsource, and a holder configured to couple the lateral-flowchromatographic assay cassette to the digital camera device in proximityto the light source, wherein the holder is adjustable to adjust theangle of the assay apparatus relative to the light source and thedigital camera device to improve at least one of a signal-to-noise ratioor a detection limit for the at least one analyte of interest; andquerying an interpretive algorithm stored in a computer readable formatin the digital camera device to convert the observed interaction of theat least one analyte of interest with the at least one ligand visualreadout to a numerical value related to the presence or amount of the atleast one analyte of interest present in the sample.29. The method of claim 28, wherein the ligand includes at least one ofan antibody, an epitope, or a nucleic acid immobilized on thelateral-flow chromatographic assay cassette.30. The method of claim 28, further comprising mixing the liquid samplewith a dye conjugate prior to applying the sample to the lateral-flowchromatographic assay cassette.31. The method of claim 30, wherein the dye conjugate is configured tointeract with at least one of the analyte of interest or the ligand toprovide a visual readout related to the presence or concentration of theanalyte of interest in the sample.32. The method of claim 28, further comprising sampling a number ofangles relative to the lateral-flow chromatographic assay cassette, thelight source, and the digital camera device to improve at least one ofthe signal-to-noise ratio or the detection limit for the at least oneanalyte of interest.33. The method of claim 28, wherein the sample includes at least onecontrol substance and at least one analyte of interest.34. The method of claim 33, further comprising timing the observing ofthe interaction of the at least one analyte of interest with the atleast one ligand immobilized on the lateral-flow chromatographic assaycassette by observing the at least one control substance.35. The method of claim 34, further comprising observing the at leastone analyte of interest when the at least one control substance appears.36. The method of claim 28, wherein the interpretive algorithm includesone or more computer storage media having stored thereon computerexecutable instructions that, when executed by one or more processors ofthe digital camera device, implement a method for interpreting thenumerical value related to the presence or amount of the at least oneanalyte present in the sample, the method comprising:receiving a user initiated request to convert the observed interactionto a numerical value; in response to the request, an act of identifyingat least one interaction of the at least one analyte of interest withthe ligand immobilized on the lateral-flow chromatographic assaycassette; capturing at least one digital photographic image of the atleast one interaction; converting the at least digital photographicimage to at least one numerical value proportional to at least one of anintensity, a density, or a number of pixels associated with the at leastone interaction; and using the at least one numerical value to determinean amount or concentration of at least one analyte present in thesample.37. The method of claim 36, the computer implemented method furtherincluding at least one of: communicating with an electronic medicalrecords system via a wireless communication channel; uploading theamount or concentration of the at least one analyte present in thesample to the electronic medical records system; querying a decisionsupport algorithm, wherein the decision support algorithm uses the atleast one numerical value to support a diagnosis of at least onecondition in a subject and to suggest a course of further evaluationand/or treatment.38. The method of claim 37, wherein the decision support algorithm isstored in a computer readable format in one or more computer storagemedia on the digital camera device.39. The method of claim 37, wherein the decision support algorithm isstored in a computer readable format on a remote database.40. The method of claim 3, wherein the ligand is one of an antibody, anepitope, a nucleic acid, and combinations thereof.

These and other objects and features of the present invention willbecome more fully apparent from the following description and appendedclaims, or may be learned by the practice of the invention as set forthhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify the above and other advantages and features of thepresent invention, a more particular description of the invention willbe rendered by reference to specific embodiments thereof which areillustrated in the appended drawings. It is appreciated that thesedrawings depict only illustrated embodiments of the invention and aretherefore not to be considered limiting of its scope. The invention willbe described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 illustrates a top view of a lateral-flow chromatographicimmunoassay cassette;

FIG. 2 illustrates the principles of multiplex detection in a singleimmunoassay cassette using multiple capture antibodies and multipledetection dyes (e.g., quantum dots);

FIG. 3 illustrates a perspective view of a diagnostic testing systemthat includes a lateral-flow chromatographic immunoassay cassette, adigital camera device, and a holder configured to couple thelateral-flow chromatographic immunoassay cassette to the digital cameradevice. FIG. 3A illustrates a prototype testing device having anillumination source, a miniature spectrophotometer, a pair of opticalfibers, and an adjustable variable angle stage holding a lateral-flowchromatographic immunoassay cassette;

FIG. 3B illustrates a detailed side view of the angle between alateral-flow chromatographic immunoassay cassette, an illuminatinglight, and a detector; FIG. 4 illustrates an exploded view of thediagnostic testing system that is illustrated in FIG. 3. FIG. 4Aillustrates a sample holder with an adjustable variable angle stage;

FIG. 5 illustrates a perspective view of the diagnostic testing systemillustrated in FIG. 3 with the digital camera device removed. FIG. 5A isa graph illustrating the relationship between the illumination angle ona lateral-flow chromatographic immunoassay cassette and a an elasticlight scattering signal obtained from the lateral-flow chromatographicimmunoassay cassette at a variety of angles and a variety of loadingconcentrations using the prototype testing device shown in FIG. 3A; and

FIG. 6 illustrates a perspective view of the holder and the lateral-flowchromatographic immunoassay cassette illustrated in FIG. 3 with thedigital camera device removed. FIG. 6A shows elastic light scatteringdata for assaying thyroid stimulating hormone dissolved in phosphatebuffered saline using the prototype testing device shown in FIG. 3A.FIG. 7 illustrates a prototype testing device having an illuminationsource, a miniature spectrophotometer, a pair of optical fibers, and anangularly variable stage holding a lateral-flow chromatographicimmunoassay cassette.

FIG. 8 illustrates an alternative embodiment of a diagnostic testingsystem that includes a lateral-flow chromatographic immunoassaycassette, a miniature spectrophotometer, a stage holding thelateral-flow chromatographic immunoassay cassette, an angularlyadjustable illumination/detection system, a power source, and a separatecomputing device.

DETAILED DESCRIPTION

A device and method for performing a point of care diagnostic test fordetecting and quantifying at least one analyte in a biological sample(e.g., a body fluid). In one embodiment, the device disclosed herein mayinclude an immunoassay apparatus (i.e., a lateral flowimmunochromatographic assay cassette) and a holder with an adjustablevariable angle stage for positioning the immunoassay apparatus relativeto a light source and a detector device to optimize elastic lightscattering. In another embodiment, the device includes an interface fora light source (e.g., an optical fiber or light pipe), an interface(e.g., a collimating lens) for a external digital imager (e.g CCD orCMOS chip), and an adjustable variable angle stage that positions alateral flow immunochromatographic assay cassette so as to optimize theangle of incidence and angle of radiation to optimize an elastic lightscattering signal from the a lateral flow immunochromatographic assaycassette. The device is based upon elastic light scattering, so thevariation in the angle of incidence and angle of reflection areoptimized to maximize signal generation due to elastic light scattering.In one embodiment, the device disclosed herein includes an immunoassayapparatus, a detector device (e.g., a digital camera) positioned tocapture at least one image of a visual output signal of the immunoassayapparatus, a light source configured to transmit at least one wavelengthof light capable of interacting with a visual signal readout produced onthe immunoassay apparatus, and a holder configured to couple theimmunoassay apparatus to the detector device in proximity to the lightsource. The angle between the light source (incident light) and thedetector device (detected light) is adjustable to improve at least oneof a signal-to-noise ratio or a detection limit. The detector devicefurther includes or can remotely access an interpretive algorithm storedin a computer readable format.

I. Lateral-Flow Chromatographic Immunoassay Cassettes and Devices forDetecting and Interpreting Results of a Lateral-Flow ChromatographicImmunoassay

Referring to FIG. 1, a typical lateral-flow chromatographic immunoassaycassette 100 is illustrated. The lateral-flow chromatographicimmunoassay cassette 100 includes a plastic housing 130 containing atest strip, which is generally a plastic strip laminated with porousmaterial that permits lateral flow of liquid. The illustratedlateral-flow chromatographic immunoassay cassette 100 includes a sampleapplication zone 110 and an analysis zone 120.

In one type of lateral-flow chromatographic immunoassay cassette, thetest strip is divided into four domains, which can be made of only onekind of material or several kinds of material (e.g., up to fourdifferent kinds of materials). The first domain is for sample addition.It functions to remove viscous and particulate materials in the sampleand also to condition the sample solution for the reactions in thefollowing domains. The second domain is a mobile-phase with a colorconjugate. In one embodiment, the color conjugate may be made fromconjugation between a visible color marker (e.g., colored beads,colloidal gold, fluorescent dyes, etc.) and a detection antibody. Thedetection antibody can bind a specific antigen in the sample (e.g., ananalyte of interest or a positive control substance) and forms anantigen-color conjugate complex. The third domain of the lateral-flowchromatographic immunoassay cassette is a solid-phase with immobilizedcapture antibody. The capture antibody can bind the antigen of theantigen-color conjugate complex and forms capture antibody-antigen-colorconjugate complex sandwich. The fourth domain is for solutionabsorption. It draws sample solution towards it continuously.

During the testing, sample added to the first domain flows to the seconddomain. If the antigen is present in the sample, it will bind the colorconjugate to form antigen-color conjugate complex. This complex thenmigrates to the third domain to bind the capture antibody and forms thecapture antibody-antigen-color conjugate complex sandwich. Since thecapture antibody is immobilized in the third domain, the sandwich showsas a visible color signal or a fluorescent signal, depending on the dyetype, on the site of the capture antibody. If there is no antigen in thesample, no sandwich can be formed and hence no visible color signal canbe seen in the third domain. This is a so-called non-competitiveimmunoassay or a sandwich assay where the amount of signal is directlyproportional to the concentration of the analyte of interest in thesample.

Lateral-flow chromatographic immunoassay cassettes can also be adaptedfor competitive immunoassays. In a competitive immunoassay, the analyteof interest in the unknown sample competes for binding to an antibodywith a labeled analyte. In a competitive assay, the labeled analyte isable to provide a known signal. In the assay, the amount of labeledanalyte bound to the antibody is measured and any reduction in the knownsignal is attributed to the presence of the analyte in the sample. Thatis, in this method, the response will be inversely related to theconcentration of analyte in the unknown. This is because the greater theresponse, the less antigen in the unknown was available to compete withthe labeled antigen.

Lateral-flow chromatographic immunoassay cassettes may be adapted forassaying a number of different analyte types. For example, immunoassaycassettes have been adapted or may in the future be adapted for bloodglucose testing, metabolic testing (e.g., thyroid stimulating hormone),blood gas and electrolytes analysis, rapid coagulation testing, rapidcardiac markers diagnostics, drugs of abuse screening, urine testing,pregnancy testing, fecal occult blood analysis, food pathogen screening,complete blood count (“CBC”), hemoglobin diagnostics, infectious diseasetesting, cholesterol screening, hormone testing, cardiac pulmonary,gastroenterology, urology, dermatology, neurology, pediatrics, surgical,public health, and veterinary and plant pathology testing, combinationsthereof, and the like.

Referring now to FIG. 2, a perspective view of a diagnostic test system200 is illustrated. The diagnostic test system 200 includes alateral-flow chromatographic assay cassette 205 and means for collectingassay data from the lateral-flow chromatographic assay cassette 205.Referring now to FIG. 2, a perspective view of a lateral-flowchromatographic immunoassay cassette that is configured for multiplexanalysis is illustrated. In the embodiment illustrated in FIG. 2, thelateral-flow chromatographic immunoassay cassette includes multipletarget antibody lines (e.g., 250—Target 1, 252—Target 2, and 254—Target3) that are each configured to interact with a selected analyte ofinterest and a control line that is configured to provide a knowreadout. The analytes of interest can be detected on the various targetlines with different colored dyes, and the like. In the illustratedembodiment, different colored quantum dots are associated with each ofthe target lines.

The lateral-flow chromatographic assay cassette 205 includes a plastichousing 207 containing a test strip, which is generally a plastic striplaminated with porous material that permits lateral flow of liquid. Theillustrated lateral-flow chromatographic immunoassay cassette 205includes a sample application zone 210 and an analysis zone 230.

When a sample 220 is applied to the lateral-flow chromatographicimmunoassay cassette 205 at the sample application zone 210, the sample220 diffuses through the strip in flow direction 225 toward the analysiszone 230. In the embodiment illustrated in FIG. 2, the analysis zone 230includes a test line 240 that includes at least one capture ligandselected for capturing at least one analyte of interest in the sample220. The analysis zone 230 further includes at least first and secondcalibration standard lines 250 and 254. Additionally, the analysis zonemay include a positive control line 270 that may be configured toprovide an indication regarding whether or not sample has diffusedthough the strip and whether or not the assay is functioning.

The analyte(s) of interest, the first and second calibration standards,and the positive control can be detected on their various target lines,252, 250, 254 and 270, respectively, with various reporters. Thereporters 260-264 for each of the various target lines, 252, 250, and254 may be the same or different. Examples of suitable reportersinclude, but are not limited to, visible and fluorescent dyes, latexbeads, enzymes, gold nanoparticles, silver nanoparticles, quantum dots,and the like. Quantum dots are nano-scale materials that can produceexcited emission at particular wavelengths depending on their size andshape. Quantum dots can be used in immunoassays where dyes havetraditionally been used. However, quantum dots are generally superior totraditional organic dyes on several counts: quantum dots are typicallymuch brighter that organic dyes (owing to their high extinctioncoefficients combined with a comparable quantum yield to fluorescentdyes) as well as their stability (i.e., much less photobleaching). Forexample, it has been estimated that quantum dots are 20 times brighterand 100 times more stable than traditional fluorescent reporters.

Emission from the various reporters (e.g., quantum dots and other dyes)can be excited by a number of sources. In the illustrated embodiment, anLED light source 280 is used illuminate the analysis zone 230 of thelateral flow assay cassette 205. Illumination by the light source 280may produce a detectable signal that includes at least one of emission(e.g., fluorescence), color, reflectance, diffuse scattering (i.e.,scattering and absorbance), elastic light scattering, chemiluminescence,chemifluorescence, transmission, or absorbance from the reporters. Alens 290 (e.g., a collimating lens) and a detector (e.g., a CCD or CMOScamera) are used to collect data from the reporters and the first andsecond calibration standards. A collimating lens and a CCD camera areused to collect the emitted light. The intensity of each of the bandsand the concentration of each of the analytes can be quantified asdescribed in detail elsewhere herein.

When the sample 220 is applied to the diffusion strip of thelateral-flow chromatographic assay cassette 205, the liquid in thesample carries the analyte of interest through the diffusion strip inflow direction 225 into the analysis zone 230 where it can be capturedby the capture ligand line 240. The first and second calibrationstandard lines 250 and 254 are selected to provide a detectable signalthat correlate to non-zero concentration values of the analyte ofinterest. For example, the first and second calibration standard lines250 and 254 may include an amount of the analyte of interest or anothermaterial pre-bound to the diffusion strip of the lateral-flowchromatographic assay cassette 205. The reporter 260 may be a diffusiblematerial that can bind to the capture ligand line 250 and the first andsecond calibration standards 250 and 254 in an amount proportional tothe amount of bound ligand is present in each line. In response toillumination by the light source, the reporter 260-264 bound to each oflines 250-254 provides a signal that can be used to calculate acalibration curves and, in turn, determine the concentration of theanalyte of interest in the sample 220. Referring now to FIG. 3, aperspective view of a diagnostic testing system 200 is illustrated. Thediagnostic testing system 200 includes a lateral-flow chromatographicimmunoassay cassette 100, a digital camera device 210, a lower cover250, and a cassette holder 230 configured to couple the lateral-flowchromatographic immunoassay cassette 100 to the digital camera device210. The diagnostic testing system 200 also includes a light source (notshown) that can be used to illuminate the lateral-flow chromatographicimmunoassay cassette 100 to permit the digital camera device 210 tocapture one or more images of the results of an assay in the analysiszone 120 of the lateral-flow chromatographic immunoassay cassette 100.

In one embodiment, the light source (not shown) can include at least oneof a camera flash, an autofocus illuminator on a camera, ambient light,sunlight, an LED light, an incandescent lamp, or a gas-discharge lamp.For example, the light source can come from micro-LED lamps that areincluded in the housing 230. The micro-LEDs can be selected to emitcertain wavelengths that are adapted for one or more assay conditions.The micro-LEDs can be powered by drawing electrical power from thebattery of digital camera device 210.

In one embodiment, at least one wavelength filter may be interposedbetween the light source and the lateral-flow chromatographicimmunoassay cassette 100. For example, if the assay is a fluorescentassay, then the wavelength filter may be used to yield a specificwavelength of light from the light source to excite fluorescent emissionfrom the assay system. Likewise, certain colored dyes may yield a bettersignal when excited by selected wavelengths of light.

In one embodiment, the light source may include at least one focusingapparatus (e.g., a collimating lens) for focusing the light source onthe lateral-flow chromatographic immunoassay cassette 100. For example,a focusing apparatus may be used to increase the amount of incidentlight on the analysis zone 120 of the lateral-flow chromatographicimmunoassay cassette 100. In another example, a focusing apparatus maybe used to focus ambient light or sunlight on the analysis zone 120 ofthe lateral-flow chromatographic immunoassay cassette 100 in order toallow the digital camera device to capture at least one image of theassay output.

In the illustrated embodiment, the cassette holder 230 includes a device240 that can allow the angle of the lateral-flow chromatographicimmunoassay cassette 100 to be adjusted relative to digital cameradevice 210 and a light source (not shown). By selectively modifyingthese angles, the lower detection limit of the assay can be extended,the signal to noise ratio can be improved, etc. In one embodiment, thedevice 240 can be adjusted manually in order to choose an angle thatoptimizes detection limit, signal to noise, and the like. In anotherembodiment, the device 240 can be coupled to a mechanical means, such asa servo motor or a gel-damped spring device that can allow the device240 to automatically sample a number of angles while the digital cameradevice 210 captures a number of images of the analysis zone 120 of thelateral-flow chromatographic immunoassay cassette 100.

In the illustrated embodiment, the digital camera device 210 is a cameraphone (e.g., an Apple brand iPhone). In other embodiments, the digitalcamera device 210 can be essentially any camera phone or digital camera.In a preferred embodiment, the digital camera device 210 is a cameraphone or digital camera that has an onboard image processing capabilityand the ability to communicate wirelessly with a database.

FIG. 3A illustrates an apparatus 300 that can be used to test therelationship between illumination angle, detection angle, andfluorescent signal. The apparatus 300 includes an illumination lightsource 320, a detector device 340, means 330 for transmitting anilluminating light from the illumination source 320 to the lateral-flowchromatographic assay cassette 100, means 350 for transmitting a signalfrom the lateral-flow chromatographic assay cassette 100 to the detectordevice 340, and an adjustable variable angle stage 310 configured foradjusting an angle of the lateral-flow chromatographic assay cassette100 in relation to an illuminating light source and a detector device.

In the illustrated embodiment, the means 330 for transmitting anilluminating light from the illumination source to the lateral-flowchromatographic assay cassette 100 includes an optical fiber. In otherembodiment, the means 330 for transmitting an illuminating light fromthe illumination source to the lateral-flow chromatographic assaycassette 100 may include at least one of a light pipe or one or morelenses. Likewise, in the illustrated embodiment, the means 350 fortransmitting a signal from the lateral-flow chromatographic assaycassette 100 to the detector device 340 includes an optical fiber. Otheroptions include at least one of a light pipe or one or more lenses. Inthe illustrated embodiment, optical fibers 330 and 350 are supported bysupports 335 and 355, respectively.

The illuminating light 330 and the and the detector device (or the means350 for transmitting a signal from the lateral-flow chromatographicassay cassette 100 to the detector device 340) are positioned toilluminate an analysis region 360 of the lateral-flow chromatographicassay cassette 100 and the adjustable variable angle stage 310 isadjustable such that an angle of illumination and an angle of reflectionare adjusted in relation to the lateral-flow chromatographic assaycassette 100 so as to optimize an elastic light scattering signal fromthe lateral-flow chromatographic assay cassette 100.

FIG. 3B illustrates the principle of adjusting the angle of theilluminating light 330 and the detector device (or the means 350 fortransmitting a signal from the lateral-flow chromatographic assaycassette 100 to the detector device 340) relative to the analysis region360 of the lateral-flow chromatographic assay cassette 100 in greaterdetail. In the embodiment illustrated in FIG. 3B, there is an angle αbetween the illuminating light 330 and the detector device (or the means350 for transmitting a signal from the lateral-flow chromatographicassay cassette 100 to the detector device 340). By adjusting the angle αwith the adjustable variable angle stage 310 (FIG. 3A), the elasticlight scattering signal from the analysis region 360 of the lateral-flowchromatographic assay cassette 100 can be optimized.

Referring now to FIG. 4, an exploded view of a diagnostic testing systemis illustrated. The diagnostic testing system includes a lateral-flowchromatographic immunoassay cassette, a camera phone device, a frontcover, a main cover, a collimating lens, and a cassette holderconfigured to couple the lateral-flow chromatographic immunoassaycassette to the camera phone. The cassette holder includes an angleadjustment mechanism that allows the user to dynamically adjust theangle between the lateral flow immunoassay cassette and the cell phoneto improve the limit of detection or to improve the signal-to-noiseratio.

The purpose of the collimating lens is to bring the focal point of thecell-phone camera (which is usually about 3 feet) to less than 2centimeters. This allows for a smaller overall package and produces afiner image that prevents the use of convoluting a blurry picture usingFourier transforms in order to produce a usable image that can beanalyzed. Furthermore, with a multi-analyte detection assay, the finerimage will prevent overlap of the target lines to improve sensitivityand accuracy.

Referring now to FIG. 4A, another embodiment of a sample holder 400 isillustrated. The sample holder 400 may, for example, be coupled directlyto a light source and a detector device. The sample holder 410 includesa cassette port 410 that is configured such that a lateral flowimmunoassay cassette 100 can be inserted into the sample holder 400. Inaddition, the cassette port 410 of the sample holder 400 includes anadjustable variable angle device 430 (e.g., a rotatable dial) thatallows angle of the cassette 100 to be adjusted relative to a lightsource and a detector device. By selectively modifying these angles, thelower detection limit of the assay can be extended, the signal to noiseratio can be improved, etc. In one embodiment, the device can beadjusted manually in order to choose an angle that optimizes detectionlimit, signal to noise, and the like. In another embodiment, the devicecan be coupled to a mechanical means, such as a servo motor or agel-damped spring device that can allow the device to automaticallysample a number of angles while a detector device collects data from thelateral-flow chromatographic immunoassay cassette 100.

In addition, the cassette port 410 of the sample holder 400 includes asealing gasket 420 disposed around the cassette port 410 that can sealthe cassette port 410 when an assay cassette 100 is inserted therein sothat ambient light does not leak into the sample holder 400. Forexample, if ambient light leaks into the sample holder 400, it couldskew results. In addition, the cassette port 410 may include aspring-loaded flap (not shown) or similar means that can seal ambientlight out of the sample holder 400 even when no cassette 100 is insertedinto the cassette port 410.

The inventors have conducted preliminary experiments using the apparatus300 illustrated in FIG. 3A and a lateral-flow chromatographicimmunoassay cassette that is set up to detect thyroid-stimulatinghormone (“TSH”). This assay uses ˜50 microliters of capillary blood,which is applied at the sample application zone to a nitrocellulosemembrane housed in the cassette. At the membrane origin are mobile phaseanti-TSH antibodies labeled with colloidal gold. A diluent is depositedon the blood spot and the blood travels the length of the membrane pasta test line (which consists of a solid phase capture antibody) and acontrol line. This is similar to the format of a home pregnancy test.The data shown in FIG. 6 illustrate that by varying the angles ofincident and reflected light it is possible to detect the presence ofcolloidal gold (e.g., signal) at the test line with varying degrees ofsensitivity. By optimizing these angles, it may be possible to extendthe lower limit of detection of the assay. That is, make it moresensitive.

For example, a standard reference range for TSH for adults is between0.4 and 5.0 μIU/mL. The therapeutic target range TSH level for patientson treatment ranges between 0.3 to 3.0 μIU/L. TSH levels for childrennormally start out much higher with age-related reference limitsstarting from about 1.3 to 19 μIU/mL for normal-term infants at birth,dropping to 0.6-10 μIU/mL at 10 weeks old, 0.4-7.0 μIU/mL at 14 monthsand gradually dropping during childhood and puberty to adult levels,0.4-4.0 μIU/mL.

No commercial TSH assay cassette currently on the market is able toprovide a visual readout for TSH level below about 0.5 μIU/mL. As such,TSH cassettes cannot currently be used for routine diagnosis ofhyperthyroidism. It is believed that by using the devices and methodsdisclosed herein, that the detection limit can be extended and that TSHcassettes can be used for routine diagnosis of hyperthyroidism and otherthyroid related endocrine conditions.

Referring now to FIG. 5, a perspective view of the diagnostic testingsystem 400 illustrated in FIG. 3 is illustrated with the digital cameradevice removed. As can be seen more clearly in FIG. 5, the diagnostictesting system 400 includes a housing 220 that is configured to couplethe digital camera device to the holder 230 and, in turn, to thelateral-flow chromatographic immunoassay cassette 100. And while thehousing 220 is adapted for fitting an iPhone or a similarly shapeddevice to the holder 230, the lower cover 250, and the lateral-flowchromatographic immunoassay cassette 100, the housing can be adapted tofit essentially any camera phone, compact digital camera, digital SLR,and the like. FIG. 5 also illustrates an end cap 260 on the lateral-flowchromatographic immunoassay cassette 100.

Referring now to FIG. 5A, a graph depicting the relationship between theillumination angle on a lateral-flow chromatographic immunoassaycassette and a fluorescent signal obtained from the lateral-flowchromatographic immunoassay cassette at a variety of angles and avariety of loading concentrations is illustrated.

Referring now to FIG. 6, a perspective view 500 of the holder 230, thelower cover 250, and the lateral-flow chromatographic immunoassaycassette 100 is illustrated. In the perspective view of FIG. 5, it ispossible to see the lateral-flow chromatographic immunoassay cassette100 as the camera device sees it. As the sample travels from the sampleapplication zone 110 and into the analysis zone 120, the camera deviceis positioned to capture an image of the result of the assay in theanalysis zone 120. Likewise, in the illustrated embodiment in FIG. 5,the camera's flash, which is positioned close to the lens, may bepositioned to illuminate the analysis zone 120. As mentioned above,however, the housing 230 may be designed to include another light sourceor the light source may come from ambient light or sunlight. FIG. 5 alsoillustrates how the camera's view of the analysis zone 120 could changeas the angle of the lateral-flow chromatographic immunoassay cassette100 with the device 240.

FIG. 6A shows preliminary results for assaying thyroid stimulatinghormone dissolved in phosphate buffered saline using the prototypetesting device shown in FIG. 3A. The limit of detection is 0.005 mIU/mL.

FIG. 7 illustrates an apparatus that can be used to test therelationship between illumination angle, detection angle, andfluorescent signal. The inventors have conducted preliminary experimentsusing a lateral-flow chromatographic immunoassay cassette that is set upto detect thyroid-stimulating hormone (“TSH”). This assay uses ˜50microliters of capillary blood, which is applied at the sampleapplication zone to a nitrocellulose membrane housed in the cassette. Atthe membrane origin are mobile phase anti-TSH antibodies labeled withcolloidal gold. A diluent is deposited on the blood spot and the bloodtravels the length of the membrane past a test line (which consists of asolid phase capture antibody) and a control line. This is similar to theformat of a home pregnancy test. The data shown in FIG. 6 illustratethat by varying the angles of incident and reflected light it ispossible to detect the presence of colloidal gold (e.g., signal) at thetest line with varying degrees of sensitivity. By optimizing theseangles, it may be possible to extend the lower limit of detection of theassay. That is, make it more sensitive.

For example, a standard reference range for TSH for adults is between0.4 and 5.0 μIU/mL. The therapeutic target range TSH level for patientson treatment ranges between 0.3 to 3.0 μIU/L. TSH levels for childrennormally start out much higher with age-related reference limitsstarting from about 1.3 to 19 μIU/mL for normal-term infants at birth,dropping to 0.6-10 μIU/mL at 10 weeks old, 0.4-7.0 μIU/mL at 14 monthsand gradually dropping during childhood and puberty to adult levels,0.4-4.0 μIU/mL.

Referring now to FIG. 10, a diagnostic testing system according toanother embodiment is illustrated. The diagnostic testing systemillustrated in FIG. 10 includes a lateral-flow chromatographicimmunoassay cassette, a miniature spectrophotometer, a stage holding thelateral-flow chromatographic immunoassay cassette, an angularlyadjustable illumination/detection system, a power source (e.g., alithium ion battery pack), and a separate computing device (e.g., atablet computer or a PDA) that can communicate with the systems eitherby a wired connection or wirelessly.

In one embodiment, the tray can be pulled out towards the user, and thelateral flow immunoassay cassette (“LFA”) placed inside. The knob thatis used to pull the tray out can also be used to move the LFA left andright to position the detection fiber (or a CCD or similar photodiode)to be able to test the different target lines, control, etc. The fineadjustment knobs are for positioning the fiber to maximize signalintensity. In the illustrated embodiment, a bifurcated cable is shown.In the bifurcated cable, the excitation and detection wavelengths travelthrough the same fiber. The bifurcated cable can be used for singleanalyte assays or for multi-analyte detection schemes with multiplecapture antibodies and multiple dyes (e.g., quantum dots). In additionto that, there are brackets to place a separate light source fiber orLED light sources if needed. In the back right is a lithium ion batterypack with a recharging circuit and external DC power plug adapter.

While the testing in the present application has been conducted with TSHcassettes, it is believed that the same or similar principles can beapplied to cassettes adapted for other types of tests.

II. Methods for Detecting at Least One Analyte of Interest in a Sample

In one embodiment, a method for detecting at least one analyte ofinterest in a sample is disclosed. The method includes (1) providing alateral-flow chromatographic immunoassay cassette that includes at leastone ligand immobilized thereon, wherein the at least one ligand iscapable of capturing an analyte of interest on the lateral-flowchromatographic immunoassay cassette (2) applying a liquid sample to thelateral-flow chromatographic immunoassay cassette, wherein the sampleincludes at least one analyte of interest, (3) coupling the lateral-flowchromatographic assay cassette to a sample holder configured to anglethe lateral-flow chromatographic assay cassette in relation to adetector device, and (4) observing the presence of the at least oneanalyte of interest by elastic light scattering. In one embodiment, thedevice includes an illumination source, a miniature spectrophotometer,at least one optical fiber capable of transmitting an illuminating lightfrom the illumination source to the lateral-flow chromatographic assaycassette, a collimating lens capable of transmitting a signal from thelateral-flow chromatographic assay cassette to the miniaturespectrophotometer, and an adjustable variable angle stage configured forholding the lateral-flow chromatographic assay cassette at an anglegreater than or less than zero degrees in relation to the illuminatinglight and the miniature spectrophotometer, wherein the illuminatinglight and the and the miniature spectrophotometer are positioned toilluminate at least a portion of the lateral-flow chromatographic assaycassette and optimize an elastic light scattering signal from thelateral-flow chromatographic assay cassette.

In another embodiment, the method includes (1) providing a lateral-flowchromatographic immunoassay cassette that includes at least one ligandimmobilized thereon, (2) applying a liquid sample to the lateral-flowchromatographic immunoassay cassette, wherein the sample includes atleast one analyte of interest, (3) observing an interaction of the atleast one analyte of interest with the at least one ligand immobilizedon the lateral-flow chromatographic immunoassay cassette with a devicethat includes a digital camera device, a light source, and a holderconfigured to couple the lateral-flow chromatographic immunoassaycassette to the digital camera device in proximity to the light source.The holder is adjustable to adjust the angle of the immunoassayapparatus relative to the light source and the digital camera device toimprove at least one of a signal-to-noise ratio or a detection limit forthe at least one analyte of interest. The method further includes (4)querying an interpretive algorithm stored in a computer readable formatin the digital camera device to convert the observed interaction of theat least one analyte of interest with the at least one ligand visualreadout to a numerical value related to the presence or amount of the atleast one analyte of interest present in the sample.

In one embodiment, a single immunoassay device may contain multipletypes of different antibodies each conjugated with different dyes (e.g.,quantum dots) and multiple capture bands each immobilized with differentantibodies. A single light source (e.g., an ultraviolet light)illuminates all dyes (e.g., quantum dots) simultaneously, and thedetector device (e.g., a digital camera) captures the emitted signalsfrom multiple bands simultaneously.

In one embodiment, analytes of interest assayed on the lateral flowimmunoassay cassettes described herein may be detected and quantified byelastic light scattering. The amount of light scattered from a selectedregion of a lateral flow immunoassay cassette (e.g., a capture band) ishighly sensitive to the amount of material in a region illuminated by anincident light. In general, elastic light scattering, coupled with angleoptimization, may be as much as 100 times more sensitive than comparablereflectance or fluorescence analysis.

In one embodiment, an ultraviolet light source is positioned at acertain angle to the LFA and the detector (e.g., a detection fiber or aminiature spectrophotometer). In one embodiment, an ultraviolet lightsource is positioned at a certain angle to the LFA and the detector(e.g., a detection fiber or a cell phone camera) on fiber (eventuallythe cell phone camera CCD). In one embodiment, a capture band may bequeried by taking a reading from the control line of the LFA as abaseline, then a reading from the capture band, and determine thedifference in photon intensity. Signal intensity (i.e., the amount ofscattered light that is detected) decreases as the concentration of theanalyte of interest increases.

In an embodiment that includes a cell phone camera or the like, thecamera's CCD will take an image. In this image, both the control andtest line will be present. The digital image will then undergo digitalsignal processing with a selected digital processing algorithm toproduce a representative image of the color bands for the control andtest simultaneously. The digital processing algorithm will then take anintegrative value based on a pre-determined area within each of thebands, and add the intensity values (0-255) of each of these pixels,producing a final intensity count. This will be compared to a standardcurved produced, which can be quantified. Internal controls, such as butnot limited to, a fluorescent marker to potentially eliminate or reducevariations in the final signal from manufacturing tolerances of the LFAmay be used to increase the robustness and reliability of the analysis.Additionally, analysis of the white portion of the LFA may be used as anadditional negative control to further improve reproducibility.

In one embodiment, the method may further include mixing the liquidsample with a dye conjugate prior to applying the sample to thelateral-flow chromatographic immunoassay cassette. In one embodiment,the dye conjugate is configured to interact with at least one of theanalyte of interest or the ligand to provide a visual readout related tothe presence or concentration of the analyte of interest in the sample.In one embodiment, the sample includes at least one control substanceand at least one analyte of interest.

In one embodiment, the timing the observing of the interaction of the atleast one analyte of interest with the at least one ligand immobilizedon the lateral-flow chromatographic immunoassay cassette by observingthe at least one control substance. For example, the TSH assay is read10 minutes after the diluent is applied. By monitoring the position ofthe wave front or the appearance of the control line, we can eliminatethe need to manually time the test. Likewise, by observing the timing ofthe appearance of a control, the most favorable time for reading theassay can be identified. These could include monitoring the movement ofthe mobile phase, monitoring the movement of the control substance,timing the movement of the mobile phase, taking sequential images of thetest result, detecting when buffer is added, detecting when liquid hastraveled the length of the membrane, and combinations thereof.

The positive control substance can also be used for calibrating thetest. This device is intended to provide quantitative results. To dothis requires calibrating the test. In one embodiment, the test may becalibrated by adding a quantity (e.g., a known quantity) of a positivecontrol substance (e.g., a solution of fluorescent particles) to thediluent. The light source will generate light at wavelengths to optimizethe detection of the test line and to illuminate the positive controlsubstance. The digital camera device can detect the amount of light thatis scattered or emitted by the positive control substance and use thisinformation to normalize the scattering or emission from the analyte ofinterest. In addition to providing calibration data, the positivecontrol substance can be used to time the reaction and to demonstratethat the assay functioned correctly. In addition, the test can befurther calibrated or quantified by including a color scale that isprinted on the body of the assay cassette adjacent to the cassettewindow. The color scale could also serve as an addition means forcalibrating the test result.

In one embodiment, an interpretive algorithm may be queried forinterpretation of the elastic light scattering signal. The interpretivealgorithm may include one or more computer storage media having storedthereon computer executable instructions that, when executed by one ormore processors, implement a method for interpreting the numerical valuerelated to the presence or amount of the at least one analyte present inthe sample. In one embodiment, the computer implemented method includes(1) receiving a user initiated request to convert the visual signalreadout of the immunoassay apparatus to a numerical value, (2) inresponse to the request, an act of identifying at least one elasticlight scattering signal of the immunoassay apparatus, (3) capturing atleast one elastic light scattering signal from the immunoassayapparatus, (4) converting the one elastic light scattering signal to atleast one numerical value proportional at least one of an intensity ordensity of the elastic light scattering signal, and (5) using the atleast one numerical value to determine an amount or concentration of atleast one analyte present in the sample. This numerical value can thenbe displayed on a screen located on the detector device and/or stored,interpreted, or sent to a database.

In one embodiment, the interpretive algorithm queried in step (4) of theabove described method may include one or more computer storage mediahaving stored thereon computer executable instructions that, whenexecuted by one or more processors of the detector device, implement amethod for interpreting the numerical value related to the presence oramount of the at least one analyte present in the sample. In oneembodiment, the computer implemented method includes (1) receiving auser initiated request to convert the visual signal readout of theimmunoassay apparatus to a numerical value, (2) in response to therequest, an act of identifying at least one visual signal readout of theimmunoassay apparatus, (3) capturing at least one digital photographicimage of the at least one visual signal readout of the immunoassayapparatus, (4) converting the at least digital photographic image to atleast one numerical value proportional to at least one of an intensity,a density, or a number of pixels in the at least one digitalphotographic image of the at least one visual signal readout of theimmunoassay apparatus, and (5) using the at least one numerical value todetermine an amount or concentration of at least one analyte present inthe sample. This numerical value can then be displayed on a screenlocated on the detector device and/or stored, interpreted, or sent to adatabase.

In one embodiment, the computer implemented method may further includeat least one of: (1) communicating with an electronic medical recordssystem via a wireless communication channel, (2) uploading the amount orconcentration of the at least one analyte present in the sample to theelectronic medical records system, or (3) querying a decision supportalgorithm, wherein the decision support algorithm uses the at least onenumerical value to support a diagnosis of at least one condition in asubject and to suggest a course of treatment.

Embodiments of the present disclosure may comprise or utilize specialpurpose or general-purpose computing devices that include computerhardware, such as, for example, one or more processors and systemmemory, as discussed in greater detail below. Embodiments within thescope of the present invention also include physical and othercomputer-readable and recordable type media for carrying or storingcomputer-executable instructions and/or data structures. Suchcomputer-readable recordable media can be any available media that canbe accessed by a general purpose or special purpose computer system.Computer-readable media that store computer-executable instructionsaccording to the invention are recordable-type storage media or otherphysical computer storage media (devices) that are distinguished frommere transitory carrier waves.

Computer-readable media that carry computer-executable instructions aretransmission media. Thus, by way of example, and not limitation,embodiments of the invention can comprise at least two distinctlydifferent kinds of computer-readable recordable media: computer storagemedia (devices) and transmission media.

Computer storage media (devices) includes RAM, ROM, EEPROM, CD-ROM orother optical disk storage, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to store desiredprogram code means in the form of computer-executable instructions ordata structures and which can be accessed by a general purpose orspecial purpose computer and which are recorded on one or morerecordable type medium (device).

A “network” is defined as one or more data links or communicationchannels that enable the transport of electronic data between computersystems and/or modules and/or other electronic devices. When informationis transferred or provided over a network or another communicationsconnection or channel (either hardwired, wireless, or a combination ofhardwired or wireless) to a computer, the computer properly views theconnection as a transmission medium. Transmissions media can include anetwork and/or data links which can be used to carry or desired programcode means in the form of computer-executable instructions or datastructures and which can be accessed by a general purpose or specialpurpose computer. Combinations of the above should also be includedwithin the scope of computer-readable media.

Further, upon reaching various computer system components, program codemeans in the form of computer-executable instructions or data structurescan be transferred automatically from transmission media to computerstorage media (devices) (or vice versa). For example,computer-executable instructions or data structures received over anetwork or data link can be buffered in RAM within a network interfacemodule (e.g., a “NIC”), and then eventually transferred to computersystem RAM and/or to less volatile computer storage media (devices) at acomputer system. Thus, it should be understood that computer storagemedia (devices) can be included in computer system components that also(or even primarily) utilize transmission media.

Computer-executable instructions comprise, for example, instructions anddata which, when executed at a processor, cause a general purposecomputer, special purpose computer, or special purpose processing deviceto perform a certain function or group of functions. The computerexecutable instructions may be, for example, binaries, intermediateformat instructions such as assembly language, or even source code.Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the described features or acts described herein.Rather, the described features and acts are disclosed as example formsof implementing the claims.

Those skilled in the art will appreciate that the invention may bepracticed in network computing environments with many types of computersystem configurations, including, personal computers, desktop computers,laptop/notebook computers, message processors, hand-held devices,multi-processor systems, microprocessor-based or programmable consumerelectronics, network PCs, minicomputers, mainframe computers, tablets,mobile telephones, PDAs, pagers, routers, switches, and the like. Theinvention may also be practiced in distributed system environments wherelocal and remote computer systems, which are linked (either by hardwireddata links, wireless data links, or by a combination of hardwired andwireless data links) through a network, both perform tasks. In adistributed system environment, program modules may be located in bothlocal and remote memory storage devices.

In particular, one or more embodiments of the invention may be practicedwith mobile consumer computing devices. Mobile consumer computingdevices or more simply, mobile consumer devices, can be any of a broadrange of computing devices designed or optimized for portability and forpersonal use. Mobile consumer devices can take a variety of forms,ranging from more traditional notebook and netbook computers to anemerging and rapidly growing market of handheld devices, including smartphones (e.g., the APPLE IPHONE, ANDROID phones, WINDOWS phones, SYMBIANphones), tablet computers (e.g., the APPLE IPAD, ANDROID tablets),gaming devices (e.g., NINTENDO or PLAYSTATION portable gaming devices,the APPLE IPOD), multimedia devices (e.g., the APPLE IPOD), andcombinations thereof. Many of these devices can enable richuser-interactivity by including combinations of output, input, and othersensory devices, such as touch- or pressure-sensitive displays (usingcapacitive or resistive technologies, for example), still and videocameras, Global Positioning System (GPS) receivers, magnetic compasses,gyroscopes, accelerometers, light sensors, proximity sensors,microphones, speakers, etc. These devices can also comprise a variety ofcommunications devices, such as combinations of cellular modems (e.g.,Global System for Mobile Communications (GSM), Code division multipleaccess (CDMA)), Wireless Fidelity (Wi-Fi) radios, Bluetooth radios, NearField Communication (NFC) devices, etc. Many mobile consumer devices areexpandable, such that a user can add new hardware and functionality notpresent during manufacture of the device. It will be appreciated that asthe market for mobile consumer devices expands and develops, thefunctionality of these devices will also expand to utilize new andimproved user-interaction devices and communications devices. Theembodiments described herein are expansive and can also utilize anyfuture developments in the field of mobile consumer devices.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. An analyte detection system, comprising: alateral-flow chromatographic assay cassette that includes a surfaceconfigured to detect an analyte in a sample; an illuminating lightsource positioned and configured to illuminate the surface of thelateral-flow chromatographic assay cassette with at least one wavelengthof light in order to yield an elastic light scattering signal inresponse to the presence of the analyte; a detector device positioned tocapture and detect the elastic light scattering signal; a sample holdercoupled to the detector device and configured to position the surface ofthe lateral-flow chromatographic assay cassette in relation to thedetector device and the illuminating light source, wherein the sampleholder includes a stage configured to position the surface relative toan angle of illumination from the illuminating light source and an angleof detection to the detector device so as to optimize the elastic lightscattering signal; and further comprising a computer readable programstored in a computer readable format and electronically coupled to thedetector device, wherein the computer readable program is configured toconvert the elastic light scattering signal to a numerical value relatedto the amount of at least one analyte present in the sample.
 2. Thesystem of claim 1, wherein an angle of illumination from theilluminating light source to the surface and an angle of reflection ofilluminating light reflecting from the surface to the detector deviceare each approximately 45°.
 3. The system of claim 1, wherein at leastone wavelength filter is interposed between the illuminating lightsource and the lateral-flow chromatographic assay cassette.
 4. Thesystem of claim 1, wherein the illuminating light source comprises atleast one of ambient light, sunlight, an LED light, an incandescentlamp, or a gas-discharge lamp.
 5. The system of claim 1, wherein theilluminating light source is configured to yield at least one wavelengthof light selected to convert the signal of the lateral-flowchromatographic assay cassette to a fluorescent emission signal.
 6. Thesystem of claim 1, wherein the illuminating light source includes atleast one focusing apparatus for focusing the light source on thelateral-flow chromatographic assay cassette.
 7. The system of claim 1,wherein optimizing the elastic light scattering signal includesimproving at least one of a signal-to-noise ratio of the elastic lightscattering signal or a detection limit for detection of the analyte. 8.The system of claim 1, wherein the angle of illumination from theilluminating light source to the surface of the lateral-flowchromatographic assay cassette ranges from about 45° to about 90° andthe angle of detection, which is defined by the angle of illuminationplus an angle of reflection of illuminating light reflecting from thesurface of the lateral-flow chromatographic assay cassette to thedetector device, ranges from about 60° to about 110°.
 9. The system ofclaim 1, wherein the sample holder is removably coupled to the detectordevice.
 10. A diagnostic testing system, comprising: a lateral-flowchromatographic assay cassette that includes a surface having at leastone ligand immobilized thereon configured to interact with an analyte ofinterest to provide a signal related to the presence of the analyte ofinterest in a sample; a sample holder configured to position thelateral-flow chromatographic assay cassette in relation to a cassettereader that includes: an illumination light source, a detector devicepositioned to capture and detect the signal related to the presence ofthe analyte, means for transmitting an illuminating light from theillumination source to the lateral-flow chromatographic assay cassette,means for transmitting a signal from the lateral-flow chromatographicassay cassette to the detector device, stage configured to position thesurface of the lateral-flow chromatographic assay cassette at an anglerelative to an angle of illumination and relative to an angle ofdetection so as to optimize an elastic light scattering signal capturedand detected by the detector device; and further comprising a computerreadable program stored in a computer readable format and electronicallycoupled to the detector device, wherein the computer readable program isconfigured to convert the elastic light scattering signal to a numericalvalue related to the amount of at least one analyte present in thesample.
 11. The diagnostic testing system of claim 10, wherein theilluminating light source comprises at least one of ambient light,sunlight, an LED light, an incandescent lamp, or a gas-discharge lamp.12. The diagnostic testing system of claim 10, wherein the illuminatinglight source includes at least one focusing apparatus for focusing thelight source on the lateral-flow chromatographic assay cassette.
 13. Thediagnostic testing system of claim 10, wherein the sample holder isconfigured to allow adjustment of the angle of the lateral-flowchromatographic assay cassette relative to the light source and thedetector device.
 14. The diagnostic testing system of claim 10, whereina limit of detection for the analyte of interest is within a standardreference range.